CalculateY
Quick Answer
A circle with radius 5 has a diameter of 10, a circumference of approximately 31.42, and an area of approximately 78.54 square units.
Common Examples
| Input | Result |
|---|---|
| Radius = 5 | D: 10, C: 31.42, A: 78.54 |
| Radius = 10 | D: 20, C: 62.83, A: 314.16 |
| Diameter = 14 | R: 7, C: 43.98, A: 153.94 |
| Circumference = 100 | R: 15.92, D: 31.83, A: 795.77 |
How It Works
All circle properties can be derived from the radius (r):
Diameter = 2 x r
Circumference = 2 x π x r (equivalently, π x Diameter)
Area = π x r²
If you know a different property, you can solve for the radius first:
From Diameter: r = Diameter / 2
From Circumference: r = Circumference / (2π)
From Area: r = √(Area / π)
These formulas rely on the mathematical constant π (pi), approximately 3.14159265. The calculator uses the full-precision value of π available in JavaScript for maximum accuracy.
Worked Example
Given a circle with radius 5: Diameter = 2 × 5 = 10. Circumference = 2 × pi × 5 = 10pi ≈ 31.42. Area = pi × 5² = 25pi ≈ 78.54. Working backward from circumference: if C = 100, then r = 100 / (2pi) ≈ 15.92, and Area = pi × 15.92² ≈ 795.77.